Pusher for screw machines



Dec. 3, 1929. F. H. MILLiGAN I 1,737,667

PUSHER FOR SCREW MACHINES Filed April 11, 1927 Patented Dec. 3, 1929 UNITED STATES FRANK H. MILLIGAN, on w nnson, vnmvron'r PUSHER FOR SCREW MACHINES Application filed April 11,

This invention relates to pushers for screw machines or other machines in which stock to be treated is fed through a chuck periodically as the work progresses. In machines of this class, it is common practice to rovide a chuck for holding the stock while 1t is being formed into a screw or otherwise shaped and in rear of the chuck to provide a pusher and pusher tube which are automatically reciprocated so that, when a screw has been formed or the other work has been performed and the formed screw or other device severed from the stock, the pusher will move rearwardly over the stock while the latter is still held in the chuck and then moved forwardly,

the chuck releasing the stock during the forward movement of the pusher. The pusher is connected to the front end of the pusher tube and is formed with a slot or plurality of slots and is spring tempered whereby during the rearward movement the pusher will yield to the stock but on the forward movement will be caused to engage and, in eflect, clamp the stock and feed the same forward. The 5 pusher, however, has failed to stand up under the severe strain to which it is subjected during rapid operation of a high-power machine and frequent renewals have been necessary, and the object of the present invention is to provide a pusher which is more durable and in which the tension is more evenly distributed than in the pushers heretofore employed. The slot in the pushers heretofore used has been formed on a straight line extending 5 longitudinally of the pusher and the spring action of the pusher has. been concentrated at the back or closed end of the slot. My invention provides a spiral slot in the pusher and it has been found that such a pusher has 40 a longer life and distributes the tension more evenly than any of the pushers heretofore known. The invention is illustrated in the accompanying drawing and will be hereinafter fully set forth.

In the drawing:

Figure 1 is an elevation of a pusher constructed in accordance with the present in vention, and

Fig. 2 is a transverse section on the line 22 of Fig. 1.

1927. Serial No. 182,780.

The pusher consists of a cylindrical tube 1 provided near its rear end with an annular enlargement 2 and at its rear end with an externally threaded stem 3 whereby it may be secured in the front end of the pusher tube. 5 The tubular body 1 is of the usual dimensions and is constructed with two diametrically opposite spiral slots 4: which open through the front end of the tube and extend from the front end nearly to the head or enlargement 2. The tube is constructed of high grade steel and is spring tempered so that the forward end of the tube tends to collapse radially so that the opposed walls of the slots may meet at their front extremities if there be no stock passing through the tube.

The slots may be extended to either the right or the left as may be preferred, and they may be disposed at any desired angle to the longitudinal axis of the pusher, but I have found that an angle of about ten degrees is proper and gives the most satisfactory results. When the pusher and pusher tube move rearwardly over the stock, the forward end of the pusher will yield to the stock, the free portions at opposite sides of the front open ends of the slots moving apart and on the return forward movement of the pusher the spring temper of the tube causes the free ends to approach so that they will firmly grip the stock and move the same forward through the chuck. The spiral formation of the slot causes the pusher to move spirally rather than on a straight line and the spring action is efiected at the middle of the slots rather 3 than at the rear end of the same as in the pushers now generally employed. Tests to which the device has been subjected show that it has greater wearing qualities than pre viously known pushers and will, therefore, g' operate efficiently through a longer period while the cost of production is no greater than that of inferior pushers.

Having thus described the invention, I claim:

1. A pusher consisting of a longitudinally split cylindrical tube having its slot forming a slight spiral and opening through its front end and terminating short of its rear end. g

2. A pusher consisting of a cylindrical tube having diametrically opposite slots formed in its wall and extending substantially longitudinally thereof and opening through the front end of the tube and terminating short 5 of the rear end thereof, the slotted portion of the tube beingspring tempered and each slot being disposed at an angle of about ten degrees to the axis of the tube whereby it will form a slight spiral.

In testimony whereof I affix m signature.

FRANK H. MILLIGA [1 8.] 

